My sister had this when she was young and she had to have special shoes made to keep her feet straight, she also used a special pillow between her feet when she was sleeping or just resting. She eventually outgrew it.
I never outgrew it, just learned how to manage it on my own by being self conscious of how I walked. Mine was caused by my hips being rotated forward in their sockets. Seeing a chiropractor helped me as well. Have you tried Shiners? That's who I saw as a kid.